Fix PR8170: Clang does not check constructor declaration that uses a template-id

[faisalv]

Summary

Clang currently does no real checking of the template argument list when a template-id is used to declare a constructor:

template<class T> struct X {

X<T*, T>(); // Clang erroneously accepts this.

};

Both gcc and edg emit an error on the above code (though one could claim the spec temp.local p1 is perhaps not as explicit as it could be in this regard)

See: https://llvm.org/bugs/show_bug.cgi?id=8170

[faisalv]

*ping*
My main question is, does it make sense to suppress diagnostics when checking the template-id, and then rewording it as I do. If it does make sense to suppress and then report a new diagnostic - is my method of suppression a reasonable one (as opposed to SFINAETrap or passing a flag around that's checked prior to emitting a diagnostic)
Thanks!

[majnemer]

lib/Sema/SemaTemplate.cpp

528 ↗

(On Diff #41206)

You could use StringifiedTemplateArgs.empty() instead.

529 ↗

(On Diff #41206)

You could hoist this bit out of the std::for_each

[faisalv]

lib/Sema/SemaTemplate.cpp

528 ↗

(On Diff #41206)

Aah yes - Will do - Thanks!

529 ↗

(On Diff #41206)

Well - I would still need some way to know that this is not the first iteration. I was trying to avoid declaring another variable or checking that the string was equal to another string (I thought the empty check would be reasonable) -do you feel strongly about the hoist?

[faisalv]

*ping*

[faisalv]

*ping*

[martell]

In case anyone comes here looking for rL300555 that should be D15006 no D15005.

Thanks

[martell]

It won't let me revert the automatically updated diff to the previous one because I am not the author.
@faisalv are you able todo this and Sorry for the confusion.

cfe/trunk/lib/Driver/ToolChains/MinGW.h

private:
 
   std::string Base;
   std::string GccLibDir;
   std::string Ver;
   std::string Arch;
   mutable std::unique_ptr<tools::gcc::Preprocessor> Preprocessor;
   mutable std::unique_ptr<tools::gcc::Compiler> Compiler;
   void findGccLibDir();
+  llvm::ErrorOr<std::string> findGcc();
 };
 
 } // end namespace toolchains
 } // end namespace driver
 } // end namespace clang
 
 #endif // LLVM_CLANG_LIB_DRIVER_TOOLCHAINS_MINGW_H

cfe/trunk/lib/Driver/ToolChains/MinGW.cpp

for (StringRef CandidateArch : Archs) {
       if (findGccVersion(LibDir, GccLibDir, Ver)) {
         Arch = CandidateArch;
         return;
       }
     }
   }
 }
 
+llvm::ErrorOr<std::string> toolchains::MinGW::findGcc() {
+  llvm::SmallVector<llvm::SmallString<32>, 2> Gccs;
+  Gccs.emplace_back(getTriple().getArchName());
+  Gccs[0] += "-w64-mingw32-gcc";
+  Gccs.emplace_back("mingw32-gcc");
+  // Please do not add "gcc" here
+  for (StringRef CandidateGcc : Gccs)
+    if (llvm::ErrorOr<std::string> GPPName = llvm::sys::findProgramByName(CandidateGcc))
+      return GPPName;
+  return make_error_code(std::errc::no_such_file_or_directory);
+}
+
 toolchains::MinGW::MinGW(const Driver &D, const llvm::Triple &Triple,
                          const ArgList &Args)
     : ToolChain(D, Triple, Args), CudaInstallation(D, Triple, Args) {
   getProgramPaths().push_back(getDriver().getInstalledDir());
 
-// In Windows there aren't any standard install locations, we search
-// for gcc on the PATH. In Linux the base is always /usr.
-#ifdef LLVM_ON_WIN32
   if (getDriver().SysRoot.size())
     Base = getDriver().SysRoot;
-  else if (llvm::ErrorOr<std::string> GPPName =
-               llvm::sys::findProgramByName("gcc"))
+  else if (llvm::ErrorOr<std::string> GPPName = findGcc())
     Base = llvm::sys::path::parent_path(
         llvm::sys::path::parent_path(GPPName.get()));
   else
     Base = llvm::sys::path::parent_path(getDriver().getInstalledDir());
-#else
-  if (getDriver().SysRoot.size())
-    Base = getDriver().SysRoot;
-  else
-    Base = "/usr";
-#endif
 
   Base += llvm::sys::path::get_separator();
   findGccLibDir();
   // GccLibDir must precede Base/lib so that the
   // correct crtbegin.o ,cetend.o would be found.
   getFilePaths().push_back(GccLibDir);
   getFilePaths().push_back(
       (Base + Arch + llvm::sys::path::get_separator() + "lib").str());